Firearm receiver



FIG. 1 is a right side perspective view of a firearm receiver showing the new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is right side view thereof. 

CLAIM The ornamental design for a firearm receiver, as shown and described. 